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    <title>ShellCheck: SC2007 – Use `$((..))` instead of deprecated `$[..]`.</title>
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    <h1>SC2007 – ShellCheck Wiki</h1>
    <a href="https://github.com/koalaman/shellcheck/wiki/SC2007">See this page on GitHub</a>
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    <h2 id="use--instead-of-deprecated-">Use <code>$((..))</code> instead of
deprecated <code>$[..]</code>.</h2>
<h3 id="problematic-code">Problematic code</h3>
<div class="sourceCode" id="cb1"><pre class="sourceCode sh"><code class="sourceCode bash"><span id="cb1-1"><a href="SC2007.html#cb1-1" aria-hidden="true" tabindex="-1"></a><span class="va">n</span><span class="op">=</span>1</span>
<span id="cb1-2"><a href="SC2007.html#cb1-2" aria-hidden="true" tabindex="-1"></a><span class="va">n</span><span class="op">=</span>$[n+1]</span></code></pre></div>
<h3 id="correct-code">Correct code</h3>
<div class="sourceCode" id="cb2"><pre class="sourceCode sh"><code class="sourceCode bash"><span id="cb2-1"><a href="SC2007.html#cb2-1" aria-hidden="true" tabindex="-1"></a><span class="va">n</span><span class="op">=</span>1</span>
<span id="cb2-2"><a href="SC2007.html#cb2-2" aria-hidden="true" tabindex="-1"></a><span class="va">n</span><span class="op">=</span><span class="va">$((n</span><span class="op">+</span><span class="dv">1</span><span class="va">))</span></span></code></pre></div>
<h3 id="rationale">Rationale</h3>
<p>The <code>$[..]</code> syntax was deprecated in Bash 2.0 and replaced
with the standard <code>$((..))</code> syntax from Korn shell</p>
<h3 id="exceptions">Exceptions</h3>
<p>None.</p>
<h3 id="see-also">See also</h3>
<ul>
<li><a
href="http://unix.stackexchange.com/questions/209833/what-does-a-dollar-sign-followed-by-a-square-bracket-mean-in-bash"
class="uri">http://unix.stackexchange.com/questions/209833/what-does-a-dollar-sign-followed-by-a-square-bracket-mean-in-bash</a></li>
</ul>
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